Abstracts

Rationale: Patients who had early postoperative interictal epileptiform discharges (IEDs) after corticoamygdalohippocampectomy (CAH) had higher risk of seizure recurrence than those without IEDs. However, the relationship between early IEDs after selective amygdalohippocampectomy (SAH) and seizure outcomes has not been well investigated. Methods: Twenty five adult patients (14 female, 11 male) who underwent transylvian SAH (11 left, 14 right) for drug resistance medial temporal epilepsy were enrolled. All the patients had mesial temporal sclerosis on the pathology report. Postoperative EEG within 30 days, other preoperative variables and seizure outcomes 1 year after surgery were obtained for analysis. Seizure outcomes were categorized as seizure-free ( Engel's I ) and recurrence ( Engel's II-IV). Another group of patients who underwent CAH (n=202) were also included for investigating the occurrence of postopretive IEDs between two different types of surgery. Chi-square and Fisher's exact tests were used for statistical analysis. Results: Fourteen patients (56%) of the SAH group and 60 (29.7%) of the CAH group had postoperative IEDs (Chi-square, p=0.008). Twenty one (84%) patients of the SAH group were seizure-free at one-year follow-up. Among them, 11 (52.4%) had postoperative IEDs. Three of the four (75%) patients who were not seizure-free had postoperative IEDs. The presence of IEDs was not associated with seizure recurrence (Fisher's exact test, p=0.6) for SAH. Gender, side of surgery, onset, age of surgery, history of febrile seizures or CNS infection were not associated with seizure outcomes in this SAH group. Conclusions: Postoperative IEDs within one month are more frequently seen in SAH than in CAH. Not like in patients of CAH, the presence of IEDs early after SAH was not a predictor of seizure recurrence. However, more SAH cases might be necessary to strengthen the evidence.